Fix functionality of selecting group in manage user form

[david-roper]

What Happened?

The manage user form has a select field that allows the admin to change the groups a user is in. However the current behaviour does not change the groups of the user and it defaults to their original groups instead.

What Did You Expect?

When an admin changes the groups a user is in the user's groups should be updated. When the form is opened again the default values of the user groups should be updated.

Operating System

Ubuntu

Browser (if applicable)

Firefox

Steps to Reproduce

Log in as admin
Go to manage user
Select view of a user
change their groups and submit
view user again.

Anything Else?

No response

[gdevenyi]

Throw this idea at claude planning mode and ask for a comprehensive plan to add here.